You are a surgeon moonlighting as a consultant in a hospital in the southwestern U.S during the early fall. The emergency department calls you to see a patient with acute abdomen. He was in his usual state of health, even working in his garage and storage shed 6 hours ago. Since then, he has developed severe abdominal pain with abdominal muscle rigidity. He also has muscle pain in his extremities and back, tremor, weakness, headache, nausea, and vomiting. Vital signs are normal though the patient is quite diaphoretic. Abdominal exam shows muscle rigidity and tenderness. Bowel sounds are normal. Labs are non-specific and include hematuria, leukocytosis, and elevations in CPK, glucose, and liver enzymes. A CT scan was negative for acute cholecystitis or acute appendicitis. EKG and troponins are negative.
On exam, you note this rash on the patient's leg:
Challenge: What's the diagnosis?
Image shown under Fair Use.